Abstract: The support has an inside surface (1A) that is basically cylindrical for approximately three fourths of the axial length from the smaller-diameter end (1B), an annular step (1C) and a remaining cylindrical internal section (1E) of increased diameter for interlocking purposes; the outside surface is basically frustoconical for a section (1G) of approximately three fourths of the axial length from the larger-diameter end (1H), and its remaining cylindrical section (1F) corresponds in diameter to the remaining cylindrical internal section (1E); and for approximately the half of the larger dimensions of the wall of the support there are perforations (3) that extend transversely in the form of slots, while enlarged perforations (5) are formed in the other approximate half of the height.